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Linear accelerator 3

Linear accelerator 3 (Linac 3) is the starting point for the ions used in experiments at CERN. It provides lead ions for the Large Hadron Collider (LHC) and for fixed-target experiments. Researchers have requested that it produce other ions in the future, including argon and xenon.

Linear accelerators use radiofrequency cavities to charge cylindrical conductors. The ions pass through the conductors, which are alternately charged positive or negative. The conductors behind them push particles and the conductors ahead of them pull, causing the particles to accelerate. Superconducting magnets ensure the protons remain in a tight beam.

Linac 3 uses up about 500 milligrams of lead per two weeks of operation. At the particles’ origin and during acceleration through Linac 3, electrons are stripped away. Eventually, all of the electrons are removed and the lead is transformed into bare nuclei, which are easier to accelerate than whole ions.